GHSA-65FC-CR5F-V7R2
Vulnerability from github – Published: 2025-08-04 16:07 – Updated: 2025-08-05 17:11A prototype pollution vulnerability in js-toml allows a remote attacker to add or modify properties of the global Object.prototype by parsing a maliciously crafted TOML input.
Impact
The js-toml library is vulnerable to Prototype Pollution. When parsing a TOML string containing the specially crafted key __proto__, an attacker can add or modify properties on the global Object.prototype.
While the js-toml library itself does not contain known vulnerable "gadgets", this can lead to severe security vulnerabilities in applications that use the library. For example, if the consuming application checks for the existence of a property for authorization purposes (e.g., user.isAdmin), this vulnerability could be escalated to an authentication bypass. Other potential impacts in the application include Denial of Service (DoS) or, in some cases, Remote Code Execution (RCE), depending on the application's logic and dependencies.
Any application that uses an affected version of js-toml to parse untrusted input is vulnerable. The severity of the impact, ranging from unexpected behavior to a full security compromise, is dependent on the application's specific code and its handling of object properties.
Patches
This vulnerability has been patched in version 1.0.2.
All users are advised to upgrade to version 1.0.2 or later to mitigate this issue. Users of all prior versions are affected.
Workarounds
If you are unable to upgrade to a patched version, the only mitigation is to ensure that any TOML input being passed to the js-toml library is from a fully trusted source and has been validated to not contain malicious keys.
References
-
This vulnerability was discovered and responsibly disclosed by siunam.
-
The Proof-of-Concept can be found at this Gist: https://gist.github.com/siunam321/f3dc4d21a5a932c67b6c11d0026f5afc
-
For more information on Prototype Pollution, see PortSwigger's explanation: https://portswigger.net/web-security/prototype-pollution
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "js-toml"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.0.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-54803"
],
"database_specific": {
"cwe_ids": [
"CWE-1321"
],
"github_reviewed": true,
"github_reviewed_at": "2025-08-04T16:07:05Z",
"nvd_published_at": "2025-08-05T01:15:42Z",
"severity": "HIGH"
},
"details": "A prototype pollution vulnerability in `js-toml` allows a remote attacker to add or modify properties of the global `Object.prototype` by parsing a maliciously crafted TOML input.\n\n### Impact\n\nThe `js-toml` library is vulnerable to Prototype Pollution. When parsing a TOML string containing the specially crafted key `__proto__`, an attacker can add or modify properties on the global `Object.prototype`.\n\nWhile the `js-toml` library itself does not contain known vulnerable \"gadgets\", this can lead to severe security vulnerabilities in applications that use the library. For example, if the consuming application checks for the existence of a property for authorization purposes (e.g., `user.isAdmin`), this vulnerability could be escalated to an authentication bypass. Other potential impacts in the application include Denial of Service (DoS) or, in some cases, Remote Code Execution (RCE), depending on the application\u0027s logic and dependencies.\n\nAny application that uses an affected version of `js-toml` to parse untrusted input is vulnerable. The severity of the impact, ranging from unexpected behavior to a full security compromise, is dependent on the application\u0027s specific code and its handling of object properties.\n\n### Patches\n\nThis vulnerability has been patched in version `1.0.2`.\n\nAll users are advised to upgrade to version `1.0.2` or later to mitigate this issue. Users of all prior versions are affected.\n\n### Workarounds\n\nIf you are unable to upgrade to a patched version, the only mitigation is to ensure that any TOML input being passed to the `js-toml` library is from a fully trusted source and has been validated to not contain malicious keys.\n\n### References\n\n- This vulnerability was discovered and responsibly disclosed by [siunam](https://github.com/siunam321).\n\n* The Proof-of-Concept can be found at this Gist: https://gist.github.com/siunam321/f3dc4d21a5a932c67b6c11d0026f5afc\n\n- For more information on Prototype Pollution, see PortSwigger\u0027s explanation: https://portswigger.net/web-security/prototype-pollution",
"id": "GHSA-65fc-cr5f-v7r2",
"modified": "2025-08-05T17:11:05Z",
"published": "2025-08-04T16:07:05Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/sunnyadn/js-toml/security/advisories/GHSA-65fc-cr5f-v7r2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-54803"
},
{
"type": "WEB",
"url": "https://github.com/sunnyadn/js-toml/commit/b125910a3f094b744c9c3571360d4b9e3a472f66"
},
{
"type": "WEB",
"url": "https://gist.github.com/siunam321/f3dc4d21a5a932c67b6c11d0026f5afc"
},
{
"type": "PACKAGE",
"url": "https://github.com/sunnyadn/js-toml"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H",
"type": "CVSS_V4"
}
],
"summary": "js-toml Prototype Pollution Vulnerability"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.